Social networks and location-based services are a hotbed of activity right now. Facebook focuses on social networking, but is branching out into other areas that support its growth. Companies like Fouresquare on the otherhand are more focused and location-based as their core service.

Now it appears Facebook decided to patent a lot of location-based service before they even existed as we know them today. One patent in particular has got the Internet buzzing as it pretty much covers what Foursquare does, but Facebook now hold a patent covering that particular system and method.

The patent in question is number 7,809,805 entitled “Systems and methods for automatically locating web-based social network members.” The abstract reads:

Systems and methods for automatically locating web-based social network members are provided. According to one embodiment, contact content including an associated GPS identifier and status for web-based social network members located at or near the same location automatically appears on a GPS-enabled device. A further exemplary system includes a GPS-enabled device configured to receive a GPS identifier and a status representing a location and a current state for a web-based social network member, a processing module that associates the received GPS-identifier and the received status, and a communications module that sends the associated GPS-identifier and status to a server comprising a web-based social network database. Contact content in a web-based social network database record in the web-based social network database is updated to include the associated GPS identifier and status for the web-based social network member.

It’s not just Foursquare this could have an impact on. Google Latitude and Gowalla are just a couple more examples of potentially infringing services. What happens next is up to Facebook.

Just like with Microsoft patenting a to-do list for programmers, this is another patent that covers pretty general system and should therefore not be part of a patent that could be used to limit competition.

Facebook is not known for suing other companies for infringing patents, and it may have no intention of going after a service like Foursquare. But because the patent exists there is always the possibility it could be used in such a way.

To look at this another way. Facebook now holds the patent protecting its own services from ever being subject to a patent lawsuit. It’s a safety net rather than a competition killer.